This invention relates generally to communications associated with data processing systems and more specifically to a dynamically configurable array of communication nodes utilizing existing communication lines.
Present day computing stations generally comprise a micro-computer/terminal, a printer to provide hard copies of data and a modem to communicate with data bases or other computers. Such computers are generally single task machines, capable of only running one applications program at a time or printing data or performing communications. Thus, it would be desirable for an external unit to operate in conjunction with the micro-computer to handle peripheral related processing such as printer control, resource sharing and on-line message handling via modem in order to free the micro-computer to handle application work.
An additional deficiency associated with present day devices is a failure to provide adequate wide area networking utilizing existing communication lines.
Presently, numerous schemes exist for exchanging data between computers and peripherals. Much attention has recently been directed to Local Area Networks (LANs) as a means for linking equipment within approximately a mile. However, these networks generally are static, i.e., once a network is installed, the topology of the network remains the same. Thus, the order of the nodes connecting computers is generally fixed and remains unchanged, providing a system with limited flexibility. Illustrative of such networks connecting computers and peripherals into LANs are Ethernet (TM), Decnet (TM) and PC net (TM).
Common network configurations, or topologies, include ring, bus and star configurations. Since each such configuration has specific advantages for specific applications, it would be desirable to provide a system capable of dynamically switching between different configurations thus providing the advantages of a plurality of individual configurations in a single system. Existing static networks, however, are incapable of dynamically switching between these types of configurations.
Present day wide area networks designed to connect computer and peripherals over large distances such as terrestrial microwave networks also do not fulfill these deficiencies. These networks require special cabling, microwave devices and interface circuitry, thereby increasing the cost per node.